1. Field of the Invention
The invention relates to an apparatus comprising first and second connector means and first and second switching means, the first and second connector means each having a signal input terminal, a signal output terminal and a control signal terminal, the first and second switching means each having first, second and third terminals, the first terminal of the first switching means being coupled to the signal output terminal of the second connector means, the second terminal of the first switching means being coupled to the signal input terminal of the first connector means, the first terminal of the second switching means being coupled to the signal output terminal of the first connector means, the second terminal of the second switching means being coupled to the signal input terminal of the second connector means, the first and second switching means being adapted to couple the second or the third terminal to the first terminal under the influence of a first or second control signal respectively, the apparatus further comprising control signal generator means having a first terminal coupled to the control signal terminals of the first and second connector means, and an output terminal for supplying the first and second control signal for the first and second switching means respectively, The invention further relates to an input-output circuit that can be used in the control signal generator means which is provided with a controller, in the apparatus.
Such apparatuses can be used in combination with other apparatuses of like construction so as to form a chain of apparatuses in which two signal paths are realized, a first `down` path and a second `up` path. The first connector means of an apparatus in the chain is coupled to a second connector means of a previous apparatus in the chain, and the second connector means of the apparatus is coupled to a first connector means of a subsequent apparatus in the chain. The signal path formed by the connections of the signal input terminals of the first connector means to the signal output terminals in the second connector means, via the first switching means, of the apparatuses in the chain is called the `down` path. The signal path formed by the connections of the signal input terminals of the second connector means to the signal output terminals in the first connector means, via the second switching means, of the apparatuses in the chain is called the `up` path.
2. Description of the Related Art
The connector means are preferably in the form of a SCART connector. This means that the apparatuses are interlinked by means of SCART cables. The control signal terminals in the connector means of the apparatuses are in that case the pins with number 10 in the SCART connectors.
It should be noted that SCART connectors and cables are well known in the art, see the magazine Funk-Technik 38(1983), heft 5, pp. 208-212.
The termination of the chain at the `up` side can be realized by a television apparatus, provided with a single connector means. In the same way one further apparatus having a single connector means, preferably a video recorder, can be connected to the `down` end of the chain.
The video signal transported via a path, such as the `up` path can have various formats, such as CVBS, Y/C or RGB. The transmission of a CVBS video signal requires only one signal line relative to ground. The transmission of the Y/C video signal requires two signal lines, and the transmission of an RGB signal requires three signal lines relative to ground. The `up` path, which realizes the signal transmission towards the television apparatus has the possibility of transmitting either one of the three video signal formats mentioned above, that is CVBS via line 19 in the SCART cable, Y and C via the lines 19 and 15, respectively, and R,G and B via the lines 15, 11 and 7, respectively.
The `down` path realizes the signal transmission towards the video recorder, and realizes a video signal transmission of either the CVBS or the Y/C format. CVBS is transmitted via the line 20 in the SCART cable, and Y and C are transmitted via the lines 20 and 7, respectively.
It should thus be noted that a signal input or output terminal does not neccessarily mean a single input or output terminal, but can each comprise one, two or three sub-terminals, dependent of the signal format (or formats) that should be transmitted via the `up` and `down` path.